When originally introduced in the Legislature in 1963 as part of Senate Bill No. 42, section 831.2 only provided immunity for "`. . . an injury caused by a natural condition of any natural lake, stream, river or beach, if at the time of the injury the person who suffered the injury was not using the property for a purpose for which the public entity intended the property to be used.'" ( Osgood v. County of Shasta (1975) 50 Cal.App.3d 586, 589 [ 123 Cal.Rptr. 442].) Following several amendments, the bill was enacted in its present form, which immunizes "any natural condition of any lake, stream, bay, river or beach."

Since the policy on which the immunity is based is not applicable to injuries occurring to nonusers on adjacent land, the immunity should not be applicable. The natural condition immunity was applied in accordance with the express legislative declaration in Osgood v. County ofShasta (1975) 50 Cal.App.3d 586, 589-590 [ 123 Cal.Rptr. 442]. In that case a water skier was killed on Lake Shasta, and recovery was sought on the ground that the configuration of the lake, its coves and inlets impairing visibility, constituted a hazardous condition when used with due care by boaters and water skiers.

The gross negligence can involve only the alleged boat docks, swim platforms and speeding watercraft at the site of the accident. (8) This is because public entities are immune from liability for injuries caused by natural conditions of unimproved public property, including but not limited to any natural condition of any lake, stream, bay, river, or beach. (§ 831.2; Osgood v. County of Shasta (1975) 50 Cal.App.3d 586, 587-588, 590-591 [ 123 Cal.Rptr. 442] ( Osgood) [in a case involving a water-skier who was struck and killed by a motorboat on Shasta Lake, the Court of Appeal found that the shoreline of a man-made lake, with its coves and inlets that allegedly impaired the motorboat's visibility, constituted a dangerous natural condition for the purposes of the section 831.2 immunity; the court affirmed a demurrer in favor of the public entity on this basis].) This natural condition immunity would defeat liability for plaintiffs' allegations that the waterway was dangerous because it had blind curves, corners and vegetation that impeded visibility, and also had narrow channels (to the extent those channels were unimproved).

(Italics added.) The meaning of this clause was placed directly in issue in Osgood v. County of Shasta (1975) 50 Cal.App.3d 586 [ 123 Cal.Rptr. 442] in which the plaintiff's decedent was killed in an accident on Shasta Lake, an artificially created lake. As a matter of semantics an artificial lake could not be regarded as "unimproved," but the Court of Appeal nevertheless affirmed dismissal of the action under section 831.2, pointing out that the last clause of section 831.2 had been amended in the legislative process to delete the word "natural" immediately before the word "lake" and to make the immunity unconditional.

" ( Id., at pp. 287-289.) In Osgood v. County of Shasta (1975) 50 Cal.App.3d 586 [ 123 Cal.Rptr. 442], the decedent was struck and killed by a motor boat while waterskiing. The appellant argued the shoreline of Shasta Lake was an extremely dangerous and hazardous condition due to the physical configuration of the lake, hundreds of coves, inlets, arms and legs which limited the visibility of motor boat operators and waterskiers throughout the over 365 miles of shoreline.

The statutory immunity conferred to public entities by section 831.2 extends "to any natural condition of any lake," regardless whether the latter be natural or artificial. ( Osgood v. County of Shasta (1975) 50 Cal.App.3d 586, 589-590 [ 123 Cal.Rptr. 442]; County of Sacramento v. Superior Court (1979) 89 Cal.App.3d 215, 218 [ 152 Cal.Rptr. 391].) Like Lake Shasta in Osgood, the Lexington Reservoir, here, is an artificial, man-made lake created by constructing a dam and used by the public for recreational activities.

By requiring that those using unimproved public property assume the risk of injury caused by natural conditions there, the Legislature assured that such areas remain open to the public. (See legis. committee com. to Gov. Code, § 831.2, West's Ann. Gov. Code (1980) p. 293; Deering's Ann. Gov. Code (1982) p. 251; see Osgood v. County of Shasta (1975) 50 Cal.App.3d 586 [ 123 Cal.Rptr. 442] [natural conditions immunity applied even though the State leased concessions and maintained facilities along shore of lake].) The rule proposed by the Bartletts would require the State to choose between immunity or raising revenues by charging users fees.

1976, ch. 1303, § 1; Stats. 1978, ch. 86, § 1; Stats. 1979, ch. 150, § 1; Stats. 1980, ch. 408, § 1) should have made explicit what is contended to be implicit: that public entities are protected by section 846 We hold that they are not. All of the following decisions were decided before the last amendment to section 846 in 1980: Cardenas v. TurlockIrrigation Dist. (1968) 267 Cal.App.2d 352 [ 73 Cal.Rptr. 69] (swimming); Rendak v. State of California (1971) 18 Cal.App.3d 286 [ 95 Cal.Rptr. 665] (hiking); Buchanan v. City ofNewport Beach (1975) 50 Cal.App.3d 221 [ 123 Cal.Rptr. 338] (surfing); Osgood v. County of Shasta (1975) 50 Cal.App.3d 586 [ 123 Cal.Rptr. 442] (water skiing); Fuller v. State ofCalifornia (1975) 51 Cal.App.3d 926 [ 125 Cal.Rptr. 586] (diving); County of Sacramento v. Superior Court ( Kuhn) (1979) 89 Cal.App.3d 215 [ 152 Cal.Rptr. 391] (floating).)

It is now generally settled that human-altered conditions, especially those that have existed for some years, which merely duplicate models common to nature are still "natural conditions" as a matter of law for the purposes of Government Code section 831.2. (See, e.g., Eben v. State of California (1982) 130 Cal.App.3d 416 [ 181 Cal.Rptr. 714] [human regulation of artificial lake's water level]; County of Sacramento v. Superior Court (1979) 89 Cal.App.3d 215 [ 152 Cal.Rptr. 391] [water level and flow of river controlled by upstream dam]; Fuller v. State of California (1975) 51 Cal.App.3d 926 [ 125 Cal.Rptr. 586] [nearby human improvements on beach caused sand buildup, resulting in shallow water]; Osgood v. County of Shasta (1975) 50 Cal.App.3d 586 [ 123 Cal.Rptr. 442] [man-made lake].) The sandbar Tessier struck, if there was one, was not built by human hands.

An important aid in this regard is the legislative history of the statute. ( Osgood v. County of Shasta (1975) 50 Cal.App.3d 586, 589 [ 123 Cal.Rptr. 442].) (1e) In 1976 the League of California Cities and other associations joined forces to develop specific legislation authorizing the imposition of fees, charges, land acquisitions, etc., by local government units for ultimate use by the school districts in alleviating the impact of rapid student population growth.